Concepts and features
R&S
®
ZNA
255User Manual 1178.6462.02 ─ 29
where r = S
21,reflected
/ S
21,direct
.
Measurement Procedure for ANSI C63.25
See the Rohde & Schwarz Application Card "Fast validation of EMC Test Sites above 1
GHz with Time-domain S
VSWR
", published on the Rohde & Schwarz internet site.
4.7.2.7 Distance-to-fault measurements
Option R&S ZNA-K2 also offers a special distance-to-fault measurement that allows
you to locate faults and discontinuities on cables and transmission lines.
Faults produce peaks on the impulse response (in the time domain) that is calculated
from the measured reflection S-parameter trace via inverse Fourier transformation. The
distance between the reference plane and the fault can then be calculated from the
propagation time, accounting for the electrical properties of the transmission line.
Moreover it is possible to define the peaks to be considered as being caused by a fault.
The following example shows the reflection at the end of a faultless open cable con-
nected to test port 2. A full one-port calibration ensures that the distance is measured
from the test port position (reference plane = distance zero). The horizontal position of
marker "M2" corresponds to the cable length of 1417 mm, the additional peak at posi-
tion "M1" is due to a bad connection between the cable and the test port.
Optional extensions and accessories
To Next Page
Loading...
